Spray booth



Oct. 11, 1938. J LUDWlG 2,132,826

SPRAY BOOTH Filed April 15, 1956 INVENTOR. L/UHN E. LUDWIE' ATTORNEY 7 Patented 0a. 11, 1938 SPRAY BOOTH John E. Ludwig, Detroit, Mich., assignor to Newcomb David Company, Inc., Detroit, Mich., a corporation of Michigan Application April 13, 1936, Serial No. 74,228

9 Claims.

My inyention pertains to a paint spraying booth for, installation in buildings where automobile es, furniture and other articles are sprayed with paint, varnish and the like.

It is an object of my invention to provide a paint spraying booth comprising an improved ventilating system whereby the ventilating air is admitted into the booth and directed therethrough in such a manner that a smooth flow of air is provided whereby eddys are eliminated and the poisonous paint infected air is carried steadily away from the attendant who is doing the spraying and the spray is properly carried to and around the object to be sprayed for depositing a suitable layer of paint or varnish thereon.

Another object of my invention is to provide a paint reclaiming spraying booth comprising means for exhausting air from the booth and efficiently depositing and preserving the waste paint spray until it can be salvaged while preventing the paint spray depositing and hardening on adjacent baffle surfaces from which it could not be efficiently salvaged.

It is also an object of my invention to provide a semi-closed ventilated paint reclaiming spray booth especially suitable for installation in a factory room for receiving articles to be sprayed therethrough and having an exhaust air outlet adjacent the floor at one side of the booth, a main air inlet entering through the roof at the opposite side of the booth through an inlet provided with a baiile deflecting plate for directing the inflowing air away from the operator and toward and around the sprayed article and toward the exhaust outlet and also comprising a high velocity air inlet projector for projecting a sheet of air downwardly adjacent the oppositeside of the article being sprayed and toward the air exhaust outlet adjacent the bottom of the housing.

It is a further object of my invention to provide an improved method of operating a semiclosed spraying booth in a factory room.

The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof will best be understood from the following description of a specific embodiment, when read in conjunction with the accompanying drawing, where like reference characters refer to similar parts throughout, and in which:

Fig. 1 is a side elevational view of a ventilated paint reclaiming spraying booth with portions broken away and sectioned to more clearly i1- lustrate the construction of such a booth in accordance with my invention;

Fig. 2 is a side elevational view thereof partly in section on the line 2-2 as shown in Fig. 1; and 6 Fig. 3 is a fragmentary sectional view illustrating a detail thereof.

Referring more particularly to Fig. 1 of the drawing, my invention comprises a spraying booth inclosed by a front wall I and a rear wall 3 and joined overhead by a roof 5. The ends of the booth are partially closed by end wall pox.- tions I and 9 which are spaced apart sufllciently to provide a doorway ll therebetween through which the automobile bodies or other articles to be sprayed may be transported in any suitable manner as on an endless conveyor (not shown). The front wall I of the booth is provided with a doorway l3 through which the attendant may enter and adjacent which he stands while spraying the objects which are transported between doorways H in the ends of the booth. The doorway l3 in the front wall also aids in ventilating the booth.

For ventilating the booth and exhausting paintladen air therefrom, I provide a cupola l5 which is mounted above the roof 5 and comprises sloping gable portions i'l'which rise above the roof 5 of the booth and which may be integral therewith or secured thereto in any suitable manner. The portion of the roof 5 upon which the cupola i5 is mounted is suitably apertured to permit the free circulation of air therethrough from the booth into the cupola and an exhaust conduit i9 is connected from a circular port 2i in the apex of the cupola. The exhaust conduit i9 is connected to the inlet of an exhaust fan 23 which is operated by a suitable electric motor 25. From the outlet of the exhaust fan, a conduit 21 is connected for trans- 40 mitting the exhausted air from the building in which the booth is installed.

For guiding the flow of air from the booth and reclaiming the finely divided paint and spray which is carried by the air, conduit means is 4 provided within the booth for connecting from the cupola to a point adjacent the lower portion of the booth. This connection is established through interconnecting conductive means comprising a. verticle plate 29 connecting down- 50 wardly from the roof of the booth directing under the front edge of the cupola, and enclosing a space between the plate 29, the end walls and the rear wall 3 of the booth. In this enclosed space, I provide a water eliminator which 55 comprises a plurality of spaced plates 3i which comprise reversely bent portions which, as shown more clearly in Fig. 2, are spaced for passing the exhaust air therebetween. From the lower edge of the plate 29, I-pivotally support a water deflecting plate 33 on a horizontal pivot bar 34 supported between the end walls of the booth.

In normal operation, the plate 33 ls held by the exhaust suction in its closed position as shown. However, a lever 35 is pivotally mounted on a pin 31 on the end wall of the booth whereby the position of the pivoted water deflecting plate 33 may be adjustably controlled as desired by turning the lever to the position indicated by the dotted lines 33.

Mounted upon the rear wall 3 of the booth, I provide four air flow conducting conduits 39, the upper ends of which are adapted to be operatively engaged and conductively connected to the exhaust cupola when the pivoted plate 33 is drawn toward the rear wall 3 of the booth in adjacent abutting relation, as shown. The air in the booth is then drawn from the booth into the lower ends of the vertical conduits 39, as indicated by the dotted arrows. To provide a closely confined air flow through the four ver-- tical tubes 39, I provide a front baiile plate 4| which is secured across the booth adjacent the front sides of the four vertical conduits 39 in any suitable manner. The lower edge. of the baille pTate 4| is curled gently toward the rear of the spray booth to provide for smoothly guiding the air under the ends of the vertical conduits. A bottom plate 43 connects between the lower ends of the conduits 39 and extends across the booth adjace the front sides of the lower ends of the condui s where it also connects with the lower edge of the baffle plate 4| which is thus supported in a slightly inclined position. The bottom plate 43 also extends around and between each of the conduits 39 to restrict the air flow therebetween.

For reclaiming the larger particles of the paint and varnish carried downwardly in the booth by the spray, I provide a water reservoir 45 on the -floor in the booth adjacent its rear wall 3. As

the air is drawn under the curled lower edge of the plate 4|, it passes adjacent the upper surface of the water in the reservoir and thence turns upwardly into the conduits 39 and centrifugal force causes the larger particles in the air to be deposited in the water. The deposited paint or varnish material settles in the water which retains it and preserves it in a convenient condition for reclamation. The reclaimed material is thus prevented from lodging and drying hard and it may be conveniently salvaged as by shoveling from the bottom of the reservoir.

In order to emciently recover the more finely divided particles of the paint and varnish which passes over the water reservoir and upwardly into the vertical conduits 39, I provide each conduit with a double opposed spray nozzle 41 which projects two cones of evenly divided water spray upwardly and downwardly in each conduit. The ascending air in the exhaust conduits 39 is completely deluged by the water sprays projecting into each conduit in the form of two opposed cones, and the finely divided particles paint and varnish are removed and carried do wardly into the water reservoir where it is properly preserved and may be conveniently removed later.

For more effectively reclaiming the material, I preferably recirculate the water from the reservoir through the spray nozzles 41 instead of taking water from an external source and continuously draining water from the reservoir and thus wasting a portion of the reclaimed material. For this purpose, I provide a suitable motor operated pump 49 which draws the water from the reservoir through its inlet conduit II and forces it out through its discharge.conduit 33 under suitable pressure into the nozzle 41 in thevertical exhaust conduits.

In order to effectively ventilate the spray booth adjacent the attendant for carrying the finely divided spray away from him and to avoid eddys in the air flow which would tend to carry the poisonous fumes back to the attendant and also to aid the attendant in properly applying a smooth coat of paint or varnish upon the object, I provide means for supplying a predetermined quantity of intake air to the booth under forced circulation. The greater volume of this air is admitted to the booth from an inlet housing 31 which is mounted upon the front portion of the roof 3 of the booth. The lower portion of the inlet housing 51 is opened for directing air into the booth and it is provided at its front edge with a large baffle plate 59 which extends across the booth and is inclined downwardly for directing the greater volume of air toward and over the object to be sprayed and,

toward the exhaust outlet. The intake air is supplied to the inlet housing through a conduit 6| connecting from a large air inlet conduit 33 which connects from a pressure intake fan 63 which may be operated by a suitable electric motor, as will be readily understood.

From the large inlet conduit 63 a portion of the inlet air is divided oil through a small pipe 61 which connects into a small inlet housing 99 mounted on the central portion of the roof I of the booth. From the small inlet housing 89 on the roof of the booth, a high velocity air inlet projector extends downwardly into the booth comprising a pair of spaced air deflector plates 1| and 13 projecting downwardly into the booth and inclining toward the rear wall thereof. The air projector plates II and 13 extend across the spray booth between the end walls 9 and define a narrow air projecting slot for projecting a narrow sharply defined stream or sheet of air 13 downwardly adjacent the rear side of the object being sprayed and toward the water reservoir as indicated by the small arrows.

Opening from the air inlet conduit 9|, I provide a factory by-pass nozzle 11 which may have an air flow controlling damper 19 therein for projecting a portion of the in-take air directly into the factory room where the spray booth is installed. The air inlet conducting conduits and the high velocity projector and the factory return nozzle are so constructed and adjusted that with the pressure in-take fan and the exhaust fan adjusted for handling equal volumes of air, one-fifth of the inlet air passes out through the factory by-pass nozzle and the other four-fifths is divided between the inlet conduits 3| and 31 con-- necting into the booth. For example, the exhaust fan is preferably set to handle ten thousand cubic feet of air per minute, the inlet fan is set for delivering the same volume, and the damper control nozzle which discharges into the factory is adjusted to discharge approximately two thousand cubic feet per minute. Thus while the exhaust fan will be pulling out ten thousand cubic feet per minute, only eight thousand cubic feet per minute will be supplied by the downwardly directed currents of air directed into the booth through the inlet conduits 3| and, and the additional two thousand cubic feet of air per minute must be taken from the factory room.

In operation, the air flows smoothly down and around the object to be sprayed as indicated by the dotted arrows, thus eliminating eddies, carrying the poisonous spray steadily away from the attendant and aiding him in properly supplying a smooth coat to the object being sprayed. As the air passes downwardly toward the water reservoir 45 on the floor, gravity aids the air flow in carrying the particles of spray toward the surface of the water. As the air passes under the lower curved edge of the deflector plate 4| centrifugal force causes the larger particles of the paint to be thrown into the water. As the air passes upwardly into the vertical exhaust conduits 39, it is thoroughly washed by the double cones of water sprayed into the conduits by the double opposed nozzles 41 therein. Since all the exhaust air must pass upwardly through the conduits, all the finely divided paint and varnish is effectively reclaimed and washed down into the water reservoir where it is preserved until it can be conveniently reclaimed as by shoveling it off of the bottom of the reservoir. As the air continues upwardly, it passes between the water eliminator plates 3| where the water is effectively deposited and the exhaust air which passes out through the exhaust conduits l9 and 21 does not carry an excessive amount of water away from the apparatus.

The water deposited in the eliminator 3| drips down upon the inclined water deflecting plate 33 where it flows downwardly upon the front surface of the plate 4| and runs off of the longer edge of this plate into the reservoir. This arrangement provides a smooth evenly distributed sheet of water flowing down the front face of the baffle plate 4| and thereby prevents the spray of paint and varnish lodging thereon where it would harden and be very difficult to remove.

When the operation of the apparatus is discontinued and the exhaust fan 23 is stopped, the baffle plate 33 swings freely forward and affords free access for convenient inspection of the condition of the lower portions of the eliminator plates.

It will be seen that I have provided an efficient.

ventilated paint reclaiming spray booth in which the paint or varnish is efflciently reclaimed and the booth is efiectively ventilated by air partially drawn from the room where. it is installed for providing a smooth flow of ventilating air in the booth which is free from eddys tending to drive the fumes back toward the attendant.

Aside from the specific embodiment of the invention herein shown and described, it will be understood that details of the construction may be altered or omitted without departing from the spirit and scope of the invention as disclosed and claimed and that I do not desire to limit my invention to the exact constructions herein set forth.

In the claims, the words paint laden" are to be understood as qualifying the air that has not had the larger particles of paint removed therefrom. W

I claim:

1. In a ventilated spraying booth the combination of a spray room having a roof, a front wall, a rear wall and partially closed end walls for passing articles continuously therethrough,

exhaust air circulating means, conduits means for conducting an therefrom and including means for defining an exhaust outlet for drawing air from the booth adjacent the bottom of the rear wall therein, inlet air circulating means, an air inlet in the front portion of said roof, conduit means connecting therefrom for transmitting a large portion of the inlet air through said air inlet, a transverse baflle plate under said air inlet in said booth and inclined downwardly toward said exhaust outlet for deflecting the air toward and around the object being sprayed and toward said exhaust outlet, a second air inlet mounted on a central portion of said roof, a high velocity air-projector for projecting a narrow stream of air across said booth downwardly adjacent the rear side of the sprayed object toward said exhaust outlet.

2. A ventilated paint reclaiming spray booth having in combination a spray room inclosed by a roof, side walls and end walls, exhaust conduit means providing an exhaust outlet in the lower portion of said booth, water spray means in said exhaust conduit means for washing the air as it is drawn upwardly through said conduit means, a water reservoir disposed under said exhaust outlet, a baflle plate disposed adjacent said exhaust conduit means, a water eliminator mounted above the upper end of said exhaust conduit means, an inclined water deflecting plate'under said water eliminator for guiding a flow of water to the inwardly directed surface of said baffle plate, exhaust air circulating means, and conduit means connecting said air circulating means to draw air upwardly from said booth through said water spray and water eliminator.

3. A ventilated paint reclaiming spray booth having in combination a spray room inclosed by a roof, side walls and end walls, open portions in said walls, exhaust conduit means for exhausting air from said booth comprising water washing means, a water eliminator disposed thereabove, a water deflecting plate disposed under said water eliminator for guiding the deposited water over exposed surfaces adjacent said air washing'means to carry the paint spray downwardly and prevent a permanent deposit #hereof and a water reservoir disposed under aid air washing means to catch the water 'eturning therefrom and to receive and preserve the reclaimed spray material in suitable condition for salvaging.

4. A ventilated paint reclaiming spray booth having in combination a spray room inclosed by a roof, side walls and end walls, open portions in said walls, conduit means for exhausting air from said booth comprising water washing means and a water eliminator disposed thereabove, a water deflecting plate disposed under said water eliminator for guiding a flow of water to pass adjacent said air washing means to carry the paint spray downwardly and prevent a permanent deposit thereof, a water reservoir disposed under said air washing means to catch the water returning therefrom and from said water eliminator, an in-take air circulating device and conduit means for conducting air therefrom to spaced points in said booth and air deflecting means for projecting the air from said inlet conduits downwardly in said booth toward said water reservoir.

5. A ventilated paint reclaiming spray booth having in combination a spray room inclosed by a roof, side walls and end walls, open portions in said walls, conduit means for exhausting air fromsaidbooth comprisingwaterwashingmeans and a water eliminator disposed thereabove, a

water deflecting plate disposed under said water eliminator for guiding a flow of water to pass adjacent said air washing means to carry the paint spray downwardly and prevent a permanent deposit thereof, -a water reservoir disposed undersaidairwashingmeanstocatchthe water returning therefrom and from said water eliminator, an in-take air circulating device, air inlet conduit means for conducting a large portion of the in-take air into said booth adjacent the front wall thereof, a baille plate for directing the volume of said air toward said water reservoir, a small conduit branching from said inlet conduit and connecting to a middle portion of said booth and high velocity air projecting means associated therewith for projecting a narrow sheet of air downwardly across said booth toward said water reservoir.

6. A ventilated paint reclaiming spray booth having in combination a spray room inclosed by a roof, side walls and end walls, exhaust conduit means providing an exhaust outlet in the lower portion of said booth, water spray means in said exhaust conduit means for washing the air as it is drawn upwardly therethrough, a water reservoir disposed under said exhaust outlet, a water eliminator mounted above the upper end of said conduit means, an inclined water deflecting plate under said eliminator for guiding a flow of water upon inwardly directed surfaces, exhaust air circulating means, conduit means connecting said air circulating means to draw air from said booth upwardly through said water spray and water eliminator, open portions in the side walls of said booth, an in-take air circulating device, conduit means for conducting air from said device into said air spray booth, and a factory bypass nozzle for by-passing a portion of the in-take air to the factory room in which the booth is installed.

7. A ventilated paint reclaiming spray booth having in combination a spray room inclosed by a roof, side walls and end walls, open portions in said walls for receiving articles to be sprayed,

exhaust air circulating means, conduit means connecting said exhaust air circulating means for drawing air from said booth and defining an exhaust outlet near the bottom therein, said exhaust conduit means including air washing means disposed therein, a water eliminator disposed thereabove, a hinged water deflecting plate connected between the upper end of said air washing means and said water eliminator whereby the water returned by the eliminator is conducted down adjacent surfaces when the suction produced by said exhaust air circulating means is sufllcient to draw the hinged water deflecting plate upwardly, and the eliminator plates are automatically opened for inspection when the exhaust suction is reduced.

8. A ventilated paint reclaiming spray booth having in combination a spray room inclosed by a roof, side walls and end walls, exhaust air circulating means, a water eliminator in said booth adjacent the rear wall thereof, air washing means disposed under said water eliminator, a water reservoir disposed under said air washing means and a hinged plate disposed between said water eliminator and said water washing conduit means to provide an air conductive connection therebetween when an exhaust suction is applied sufllcient to draw the plate upwardly and whereby the plate opens automatically and provides for convenient inspection of said eliminator when the exhaust suction is reduced.

9. A paint reclaiming spray booth having in combination an exhaust conduit opening to the lower portion of the booth, a water spray in said conduit for washing the air as it is drawn upwardly through said conduit, asurface exposed to the paint spray, located above said conduit opening and between said conduit and the source of said paint spray, a fllm of water covering and flowing downwardly on said surface and a water reservoir disposed under said opening and extending beneath said surface to catch the water as it flows from said surface as well as the,

water returning from the water spray means and to receive and preserve the reclaimed spray material in suitable condition for salvaging.

JOHN E. LUDWIG. 

